Quaternary bismuth alloy



Patented May 6, 1952 QUATERNARY BISMUTH ALLOY Oscar N. Carlson andHarley A. Wilhelm, Ames, Iowa, assignors to the United States of Americaas represented by the United States Atomic Energy Commission No Drawing.Application December 13, 1949, Serial No. 132,796

3 Claims. 1

This invention deals with a bismuth alloy and, in particular, with aquaternary bismuth alloy containing lead, tin and thallium.

It is an object of this invention to provide a bismuth alloy which ischaracterized by a low melting point.

It is another object of this invention to provide a bismuth alloy whichis characterized by a high resistance to corrosion.

It is still another Object of this invention to provide a bismuth alloywhich is characterized by a low'neutron capture cross-section.

These and. other objects are accomplished by providing an alloycontaining from 55 to 65% by weight of bismuth, from 19 to 22% by Weightof lead, from 17 to 18% by weight of tin and from 3 to 5 by weight ofthallium.

It has been found that while the ternary system, without thallium, has aeutectic composition of 50% bismuth, 32% lead and 18% tin with a meltingpoint of 96 C., the same alloy with thallium added, when cooled from itsmolten condition, starts to solidify at 112 C. and is completelysolidified at 95 C. From this, it seemed that thallium hardly had anyreducing effect on the melting point of the ternary eutectic.

It was found by the inventors that the combination of a higher bismuthcontent than that of the quaternary alloy with a lower thallium content,namely, a mixture containing from 55 to 65% bismuth and from 3 to 5%thallium, had a still lower melting point than any of those experiencedwith the alloys previously made and investigated.

One example of the alloys of this invention consisted of 56.3% bismuth,21.4% lead, 17.4% tin and 4.9% thallium and had a melting point of 91 C.

Another embodiment of this invention is the following alloy: 60.3%bismuth, 19.4% lead, 17.3% tin and 3.0% thallium; its melting point wasfound to be between 88 and 89 C.

The alloys of this invention, on account of their low melting point, areexcellently usable as coolants. Due to their low thallium content, theyhave a. very low neutron capture cross-section so that they may beadvantageously used as coolants for atomic power piles and the like.

The alloys may be prepared by any method customary in the art.

It will be understood that this invention is not to be limited to thedetails given herein but that it may be modified within the scope of theappended claims.

What is claimed is:

1. An alloy consisting substantially of from to bismuth, from 19 to 22%lead, from 17 to 18% tin and from 3 to 5% thallium.

2. An alloy consisting of 56.3% bismuth, 21.4% lead, 17.4% tin and 4.9%thallium.

3. An alloy consisting of 60.3% bismuth, 19.4% lead, 17.3% tin and 3.0%thallium.

OSCAR N. CARLSON. HARLEY A. WILHELM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,117,282 Austin May 17, 1938FOREIGN PATENTS Number Country Date 37,913 Norway Sept. 24, 1923

1. AN ALLOY CONSISTING SUBSTANTIALLY OF FROM 55 TO 65% BISMUTH, FROM 19TO 22% LEAD, FROM 17 TO 18% TIN AND FROM 3 TO 5% THALLIUM.